54491-23-5

A convenient preparative method of obtaining 2,2,4,5,5-pentaalkyl-δ-valerolactones 2a-d or 2,2,4,4-tetraalkyl-γ-butyrolactones 4a-e by the acid-catalyzed lactonization of 3-cyclopropylalkanoic acids, and for obtaining bicyclo-γ-lactones 6a-d from bicyclic 2-cyclopropylalkanoic acids 5a-d is presented.

The first catalytic approach to the nucleophilic addition of silyl ketene acetals 2 to epoxides 1 is reported. The defined protocol is metal-free using tetrabutylammonioum fluoride as the catalyst. It works in a very efficient manner under solvent-free co

Castrate-resistant prostate cancer (CRPC) is a fatal, metastatic form of prostate cancer. CRPC is characterized by reactivation of the androgen axis due to changes in androgen receptor signaling and/or adaptive intratumoral androgen biosynthesis. AKR1C3 is upregulated in CRPC where it catalyzes the formation of potent androgens. This makes AKR1C3 a target for the treatment of CRPC. AKR1C3 inhibitors should not inhibit AKR1C1/AKR1C2, which inactivate 5α-dihydrotestosterone. Indomethacin, used to inhibit cyclooxygenase, also inhibits AKR1C3 and displays selectivity over AKR1C1/AKR1C2. Parallel synthetic strategies were used to generate libraries of indomethacin analogues, which exhibit reduced cyclooxygenase inhibitory activity but retain AKR1C3 inhibitory potency and selectivity. The lead compounds inhibited AKR1C3 with nanomolar potency, displayed >100-fold selectivity over AKR1C1/AKR1C2, and blocked testosterone formation in LNCaP-AKR1C3 cells. The AKR1C3·NADP +·2′-des-methyl-indomethacin crystal structure was determined, and it revealed a unique inhibitor binding mode. The compounds reported are promising agents for the development of therapeutics for CRPC.

Intramolecular cyclisation of ω-alkenoic acids and alkenols can be achieved using a catalytic amount of Cu(OTf)2 to afford lactones and cyclic ethers, offering a practical alternative to existing catalysts.

(Chemical Equation Presented) Intramolecular additions of hydroxyl or carboxyl groups to inert olefins catalyzed by simple silver(I) triflate are described. Good to excellent yields can be obtained for a range of substrates under relatively mild conditions. This reaction represents one of the simplest methods to construct cyclic ethers or lactones.

Enolates generated from α-bromo esters by the reduction with Bu6CrLi3 react with oxiranes to afford γ-hydroxy esters and β-hydroxy esters, depending on the Lewis acid used as a promoter.

During preparation of a pharmaceutically active, N-benzylated indole derivative from 4-keto acid and N1-benzylated phenylhydrazine precursors, the N-unsubstituted indole analogue arose as a significant byproduct.The proportion of debenzylated indole was greater with α-alkylated rather than straight-chain keto acids and the byproduct was fully suppressed when a keto ester was substituted for the keto acid.The benzylic group was shown to have eliminated as the amine and 15N label incorporation demonstrated terminal phenylhydrazine nitrogen incorporation in the indole byproduct only, an exception to the usual course of the Fischer indolization reaction.A ring-chain equilibration in the ketimino acid intermediate is proposed to account for the competing pathway.

The reaction of substituted 4-pentenonitriles with 50 percent sulphuric acid at 100 deg C afforded γ-lactones in moderate to good yield.